RU2404923C1 - Composition for making thin film based on system of double oxides of zirconium and titanium - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used in electronic engineering, lighting and construction industry. The composition is obtained by preparing a film-forming solution based on 96 wt % ethyl alcohol, 6.68-10.02 wt % crystalline hydrate of zirconium oxochloride and 3.34-5.01 wt % tetraethoxytitanium. The obtained solution is deposited onto a substrate and thermally treated.

EFFECT: invention enables to obtain thin films of titanium zirconate with a stable structure with high value of refractive index.

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Description

The invention relates to a technology for producing thin-film materials based on a double oxide system used in rapidly developing fields of electronic engineering and lighting industry, the construction industry, including integrated circuit technologies; as corrosion-resistant, decorative, filtering and redistributing radiation coatings.

A known composition for producing a film of zirconium dioxide (application for invention No. 93014629/33, 6 С04В 41/65, С04В 35/48, publ. 1995.06.09), used for coating glass. The composition for obtaining a film of zirconium dioxide includes crystalline zirconium oxychloride and contains 0.1 ... 1 wt.% Cobalt nitrate. The invention allows to reduce energy consumption and increase the productivity of the process of coating the base with a coating thickness of more than 100 nm.

The disadvantages of the known composition include the instability of the properties of the proposed films over time, due to structural transformations of polymorphic modifications of zirconium dioxide. A known composition for producing a thin film based on a system of double zirconium and germanium oxides (RF patent No. 2343118, C01G 25/02, C01G 17/02, publ. 10.01.09), which includes the preparation of a film-forming solution from ethanol, crystalline oxochloride hydrate zirconium and germanium tetrachloride with subsequent application of this solution to the substrate and stepwise heat treatment, in the following ratio of components, wt.%: zirconium oxochloride - 3.8-9.0; germanium tetrachloride - 3.0-7.1; ethyl alcohol - the rest.

The disadvantages of the known composition include low values of 1.97 of the proposed films, which significantly reduces the possibility of their use as light-distributing coatings.

A known composition for producing a thin film based on zirconium and silicon oxides (R.V. Gryaznov, L.P. Borilo, V.V. Kozik, AMShulpekov. Thin films based on SiO ₂ and ZrO ₂ obtained from solutions // Inorganic materials . 2001. T.37. No. 7, S.828-831), selected as a prototype. Film-forming solutions are prepared from tetraethoxysilane, ethyl alcohol and zirconium oxochloride crystalline hydrate and applied to the substrates by centrifugation followed by heat treatment to the corresponding oxides in the concentration range from 0 to 100 wt.% Zirconia. A disadvantage of the known composition is the low values of refractive indices, which impairs the properties of light-distributing coatings, as well as the strictly specified concentrations of silicon and zirconium oxides, which ensure the formation of a chemical compound in the system (67 wt.% Zirconium dioxide), complicate the reproducibility of the process.

The objective of the invention is to develop a composition for producing a thin film based on a system of double zirconium and titanium oxides, leading to the formation of a chemical compound (titanium zirconate), which ensures the stability of the structure, physico-chemical and target properties in a wide range of concentrations, as well as achieving high values refractive index when used as redistributing radiation coatings.

The problem is solved in that in the composition for producing a thin film based on a double oxide system, including the preparation of a film-forming solution based on 96 wt.% Ethanol, crystalline zirconium hydroxide and organometallic compounds based on an element of group IV of the Periodic system, followed by applying to the substrate and by heat treatment, according to the invention, tetraethoxy titanium is used as the organometallic compound in the following ratio of components, wt.%:

Zirconium oxochloride crystalline hydrate - 6.68-10.02;

Tetraethoxy titanium - 3.34-5.01;

96 wt.% Ethyl alcohol - the rest.

Among thin-film materials, films based on zirconium dioxide obtained by deposition from film-forming solutions (POR) are widely used, but the use of films of pure zirconium dioxide is limited. This is due to polymorphic transformations of the main crystalline modifications. To prevent bulk inversions, zirconia is stabilized by the introduction of titanium oxide structurally close to it, which leads to the formation of a chemical compound of zirconium titanate (ZrTiO ₄ ) with an orthorhombic structure in the film. The presence of zirconium titanate allows you to maintain high and stable values of the refractive index in films based on the ZrO ₂ -GeO ₂ binary oxide system in the concentration range from 40 to 60 mol% TiO ₂ for a long time.

To obtain thin films based on the system of double zirconium and germanium oxides (ZrO ₂ -TiO ₂ ), a film-forming solution is prepared using 96 wt% ethyl alcohol preliminarily distilled, and zirconium oxochloride is added in the form of ZrOCl ₂ · 8H ₂ O crystalline hydrate At room temperature, ZrOCl ₂ · 8H ₂ O is dissolved in ethanol with periodic stirring for 1-3 hours, depending on the concentration of zirconium oxochloride. Then, tetraethoxy titanium Ti (OC ₂ H ₅ ) ₄ is added to the film-forming solution. After maturation of the film-forming solution for 0.5-5 hours, depending on the concentration of zirconium oxochloride, it is applied by centrifugation on a MPW-340 centrifuge at a speed of 3000-5000 rpm on substrates of glass, quartz and single-crystal silicon, then stepwise heat treatment to form oxides in a thin film.

The most acceptable temperature for the storage of POR should be considered a temperature in the range of 22-25 ° C, for 2-6 months, depending on the concentration of zirconium oxochloride.

For the preparation of solutions using dishes of the second accuracy class.

The following are examples illustrating the invention.

Example 1

To prepare 100 ml of a film-forming solution, it is necessary to take 10.02 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethanol, then add 3.60 ml of tetraethoxy titanium with a density of 1.08 g / cm ³ and bring to a volume of 100 ml ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 40 mol% TiO ₂ is obtained and 70 mol.% ZrO ₂ 75 nm thick.

Example 2

To prepare 100 ml of a film-forming solution, it is necessary to take 8.35 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethanol, then add 4.50 ml of tetraethoxy titanium with a density of 1.08 g / cm ³ and bring to a volume of 100 ml ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 50 mol% TiO ₂ is obtained and 50 mol.% ZrO ₂ 73 nm thick.

Example 3

To prepare 100 ml of a film-forming solution, it is necessary to take 6.68 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethanol, then add 5.41 ml of tetraethoxy titanium with a density of 1.08 g / cm ³ and bring to a volume of 100 ml ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 60 mol% TiO ₂ is obtained and 40 mol.% ZrO ₂ with a thickness of 68 nm.

The table shows the physicochemical properties of the ZrO ₂ -TiO _{2 system} , depending on the composition of the starting components. From the obtained data it can be seen that films of composition from 40 to 60 wt.% TiO ₂ content have stable properties due to the formation of a chemical compound (zirconium titanate ZrTiO ₄ with an orthorhombic structure) in a thin film, compared with compositions containing 30 and 70 wt.% TiO ₂ . High values of the refractive index in the obtained films allow their use in light-distributing, protective, energy-saving coatings, as well as interference filters in projection equipment to prevent harmful thermal effects.

Physico-chemical properties of the films of the ZrO ₂ -TiO _{2 system} , depending on the composition of the starting components Parameter Film composition The content of TiO ₂ in the film ZrO ₂ -TiO ₂ , mol.% thirty 40 fifty 60 70 Film thickness, nm 75 88 88 88 96 Refractive index, n 1.96 2.20 2.20 2.20 2.26 Adhesion F, MPa 1.85 1.96 1.96 1.96 1,63

Claims (1)

The composition for producing a thin film based on a double oxide system includes the preparation of a film-forming solution based on 96 wt.%, Ethyl alcohol, zirconium oxochloride crystalline hydrate and an organometallic compound based on an element of group IV of the Periodic system, followed by coating and heat treatment, characterized in that as an organometallic compound, tetraethoxy titanium is used in the following ratio of components, wt.%:
Zirconium oxochloride crystal hydrate 6.68-10.02 Tetraethoxy titanium 3.34-5.01 96 wt.%, Ethyl alcohol Rest